openstack/taskflow
Code Issues Proposed changes

Merge "Remove task_action state checks"

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Jenkins 2013-10-17 04:21:36 +00:00 committed by Gerrit Code Review
commit aeb8fb9678
2 changed files with 48 additions and 33 deletions
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37
taskflow/engines/action_engine/task_action.py
View File

@ -28,8 +28,6 @@ LOG = logging.getLogger(__name__)
RESET_TASK_STATES = (states.PENDING,)
SAVE_RESULT_STATES = (states.SUCCESS, states.FAILURE)
ALREADY_FINISHED_STATES = (states.SUCCESS,)
NEVER_RAN_STATES = (states.PENDING,)
@contextlib.contextmanager
@ -55,16 +53,11 @@ class TaskAction(base.Action):
def uuid(self):
return self._id
def _change_state(self, engine, state,
result=None, progress=None, force=False):
def _change_state(self, engine, state, result=None, progress=None):
"""Update result and change state."""
old_state = engine.storage.get_task_state(self.uuid)
state_check = states.check_task_transition(old_state, state)
if not force and not state_check:
# NOTE(harlowja): if we are forcing this state change, we don't
# care if the state transition should be ignored, if it's not being
# forced then we just ignore this state change.
return
if not states.check_task_transition(old_state, state):
return False
if state in RESET_TASK_STATES:
engine.storage.reset(self.uuid)
if state in SAVE_RESULT_STATES:
@ -74,6 +67,7 @@ class TaskAction(base.Action):
if progress is not None:
engine.storage.set_task_progress(self.uuid, progress)
engine._on_task_state_change(self, state, result=result)
return True
def _on_update_progress(self, task, event_data, progress, **kwargs):
"""Update task progress value that stored in engine."""
@ -86,16 +80,17 @@ class TaskAction(base.Action):
LOG.exception("Failed setting task progress for %s (%s) to %0.3f",
task, self.uuid, progress)
def _force_state(self, engine, state, progress, result=None):
self._change_state(engine, state,
result=result, progress=progress, force=True)
def _change_state_update_task(self, engine, state, progress, result=None):
stated_changed = self._change_state(engine, state,
result=result, progress=progress)
if not stated_changed:
return False
self._task.update_progress(progress)
return True
def execute(self, engine):
if engine.storage.get_task_state(self.uuid) in ALREADY_FINISHED_STATES:
# Skip tasks that already finished.
if not self._change_state_update_task(engine, states.RUNNING, 0.0):
return
self._force_state(engine, states.RUNNING, 0.0)
with _autobind(self._task,
'update_progress', self._on_update_progress,
engine=engine):
@ -106,15 +101,15 @@ class TaskAction(base.Action):
failure = misc.Failure()
self._change_state(engine, states.FAILURE, result=failure)
failure.reraise()
self._force_state(engine, states.SUCCESS, 1.0, result=result)
self._change_state_update_task(engine, states.SUCCESS, 1.0,
result=result)
def revert(self, engine):
if engine.storage.get_task_state(self.uuid) in NEVER_RAN_STATES:
if not self._change_state_update_task(engine, states.REVERTING, 0.0):
# NOTE(imelnikov): in all the other states, the task
# execution was at least attempted, so we should give
# task a chance for cleanup
return
self._force_state(engine, states.REVERTING, 0.0)
with _autobind(self._task,
'update_progress', self._on_update_progress,
engine=engine):
@ -125,5 +120,5 @@ class TaskAction(base.Action):
except Exception:
with excutils.save_and_reraise_exception():
self._change_state(engine, states.FAILURE)
self._force_state(engine, states.REVERTED, 1.0)
self._force_state(engine, states.PENDING, 0.0)
self._change_state_update_task(engine, states.REVERTED, 1.0)
self._change_state_update_task(engine, states.PENDING, 0.0)

44
taskflow/states.py
View File

@ -128,7 +128,7 @@ def check_flow_transition(old_state, new_state):
## Task state transitions
# https://wiki.openstack.org/wiki/TaskFlow/States_of_Task_and_Flow#Task_States
_ALLOWED_TASK_TRANSITIONS = [
_ALLOWED_TASK_TRANSITIONS = frozenset((
(PENDING, RUNNING), # run it!
(RUNNING, SUCCESS), # the task finished successfully
@ -141,17 +141,37 @@ _ALLOWED_TASK_TRANSITIONS = [
(REVERTING, FAILURE), # revert failed
(REVERTED, PENDING), # try again
]
_ALLOWED_TASK_TRANSITIONS.extend(
# NOTE(harlowja): the task was 'killed' while in one of the below 'a'
# NOTE(harlowja): allow the tasks to restart if in the same state
# as a they were in before as a task may be 'killed' while in one of the
# below states and it is permissible to let the task to re-enter that
# same state to try to finish
(REVERTING, REVERTING),
(RUNNING, RUNNING),
# NOTE(harlowja): the task was 'killed' while in one of the starting/ending
# states and it is permissible to let the task to start running or
# reverting immediately
(a, b)
for a in (REVERTED, REVERTING, RUNNING)
for b in (RUNNING, REVERTING)
if a != b
# reverting again (if it really wants too)
(REVERTING, RUNNING),
(RUNNING, REVERTING),
))
_IGNORED_TASK_TRANSITIONS = [
(SUCCESS, RUNNING), # already finished
(PENDING, REVERTING), # never ran in the first place
(REVERTED, REVERTING), # the task already reverted
]
# NOTE(harlowja): ignore transitions to the same state (in these cases).
#
# NOTE(harlowja): the above ALLOWED_TASK_TRANSITIONS does allow
# transitions to certain equivalent states (but only for a few special
# cases)
_IGNORED_TASK_TRANSITIONS.extend(
(a, a) for a in (PENDING, FAILURE, SUCCESS, REVERTED)
)
_ALLOWED_TASK_TRANSITIONS = frozenset(_ALLOWED_TASK_TRANSITIONS)
_IGNORED_TASK_TRANSITIONS = frozenset(_IGNORED_TASK_TRANSITIONS)
def check_task_transition(old_state, new_state):
@ -161,11 +181,11 @@ def check_task_transition(old_state, new_state):
should be ignored, it returns False. If transition is not
valid, it raises InvalidStateException.
"""
if old_state == new_state:
return False
pair = (old_state, new_state)
if pair in _ALLOWED_TASK_TRANSITIONS:
return True
if pair in _IGNORED_TASK_TRANSITIONS:
return False
# TODO(harlowja): Should we check/allow for 3rd party states to be
# triggered during RUNNING by having a concept of a sub-state that we also
# verify against??